1. Field of the Invention
The proposed device relates to an aerodynamic drag and noise reduction devices for vehicle roof racks, in particularly for use with assemblies for carrying articles on a vehicle's roof rack. e.g. a ski rack. More specifically, the proposed device is aimed at aerodynamic, sonic, and aesthetic improvements, and physical protection for roof mounted ski and/or snowboard article carriers, as well as to providing a platform for logos, brand names or other graphic designs.
2. Description of Prior Art
Many ski rack attachments or units, i.e., the articles that affix to a vehicle's roof cross bars or roof rack system to hold skis and/or snowboards (“ski racks”), have an essentially vertical forward facing presentation on the top of a vehicle. A single ski rack unit generally consists of two elongated rigid portions with a hinge device at one end and a latch device at the other, activated by an actuator device, such as a depressible pad or button. Flexible gripping strips, made of rubber or similar material, are affixed to the interfacing surfaces of the elongated rigid portions. There are two such identical units, one affixed to the forward cross bar and the other to the rear cross bar. Skis and/or snowboards are secured by placing them between the flexible gripping strips of both parts and employing the latching devices. Whether ski racks are being used to transport skis and/or snowboards or not, the ski racks present with a non-uniform, multi-component surface comprised of various materials. Ski racks may also present with gaps or channels, such as between the flexible gripping strips, through which air may pass.
While a vehicle with roof mounted ski racks is in forward motion, whether carrying skis and/or snowboards or not, the ski rack's front facing profile, particularly on the forward ski rack, is exposed to airflow and environmental elements. The exposed ski rack increases aerodynamic drag on the vehicle resulting in decreased fuel efficiency and various airflow disturbances caused by the exposed ski rack increases noise, often including whistling, and buffeting. The exposed orientation of the ski rack also leaves the ski rack susceptible to damage from flying road debris and the elements.
Published studies such as “Aerodynamics of Vehicle Add-Ons,” ICME09-FM-27, Alam, et al. (2009) reveal that more than 80% of a vehicle's power is required to overcome aerodynamic drag and that roof rack components, like ski racks, can increase aerodynamic drag from 5-20% at driving speeds between 37 and 75 MPH. Studies, such as the aforementioned study, also reveal that with increased drag comes decreased fuel efficiency and subsequent higher annual fuel costs to consumers, increased carbon dioxide emissions, and increased noise generation that is disruptive to vehicle passengers.
In addition, many consumers also tend to leave their ski racks mounted to their vehicles even when not transporting skis or snowboards as removal and reattachment of ski racks, and other roof rack article carriers, between uses may not be convenient or desirable.
Finally, simple aerodynamic fairings, generally planar plastic parts that attach are sometimes employed in front of the forward cross bar, providing an angled surface for wind deflection from the roof line over the forward cross bar, or a portion of it. While these devices may reduce aerodynamic drag and noise generation with respect to cross bars depending on configuration, they also tend to direct airflow directly into the forward presenting portion of a roof rack article carrier, e.g. a ski rack, thus increasing the aerodynamic drag associated with that article carrier. e.g., ski rack.
Attempts have been made heretofore to reduce the aerodynamic drag created by vehicle roof mounted article carriers such as ski racks, bicycle racks, etc.
U.S. Pat. No. 4,456,158 issued on Jun. 26, 1984 to K. Wertz, et al. discloses a “wind deflector” for a scissors-type ski rack. The wind deflector portion is oriented in the front portion of the ski rack unit, and is secured to the ski rack unit by an integral T-shaped component that is clamped down between the flexible gripping strips. The wind deflector is a single extruded piece with tapered end caps.
US Patent Application Publication 2011/0079621 A1 (Published on Apr. 7, 2011; inventors: W. Byers, et al.) discloses a pivoting frame for various article carrying platforms, including diagonal ski racks. This application also discloses an optional simple fairing that mounts to the frame of the article carrier.
U.S. Pat. No. 6,827,245 B1 issued on Dec. 7, 2004 to C. Yetka discloses an aerodynamic container for use on the front portion of skis or snowboards when the skis or snowboards are clamped into a vehicle's ski rack.
However, none of the known prior art devices of which the applicants are aware exists for providing efficient reduction of aerodynamic drag and noise generated by horizontal scissor-type ski racks simultaneously with improvement in aerodynamic performance and protection of ski racks from environmental damage.
Therefore, there exists a need for an apparatus that is lightweight, easily attachable and removable, which is capable of reducing aerodynamic drag, reducing noise, and enveloping and protecting roof rack mounted article carriers, like ski racks.